Abstract:
In a single-gun, plural-beam cathode ray tube, for example, a color picture tube, in which the plurality of beams originate in spaced relation to each other and are directed toward the receiving screen along convergent paths so as to impinge on the screen after intersecting each other at a location in the tube between the beam producing means and the screen, individual prefocusing electron lenses are provided for the beams at positions between the beam producing means and the location where the beams intersect and are operative to partially focus the respective beams on the screen, and a main focusing electron lens common to all of the beams is provided to complete the focusing of the beams on the screen, such main focusing lens having an optical center and being positioned to dispose the optical center thereof substantially at the location where the beams intersect for diminishing the effects of certain optical aberrations.
Abstract:
In a cathode ray tube of the single-gun, plural-beam type in which the plurality of beams are made to intersect each other at a location in the tube between the beam producing means and the screen, a focusing lens for focusing all of the beams on the screen is made up of a plurality of lens components arranged in axial succession and defining an optical center of the focusing lens disposed within the latter, and such focusing lens is positioned so that the optical center thereof is substantially at the location where the beams intersect. The lens components of the focusing lens may be symmetrical or asymmetrical with respect to the optical center, and in the latter case may be effective to compensate for any optical aberrations imparted to certain of the beams when the latter are converged to intersect by means of an auxiliary lens.
Abstract:
A shielding mechanism for isolating the positively charged neck of a color cathode ray tube from a plurality of cathodes within such neck, in which a steel plate covers the open end of a grid which housed the aforementioned cathodes. The grid also has formed therein separators to eliminate the effects of intercathode electric field reaction which may result from dissimilar potentials of the cathodes.
Abstract:
A signal control system for controlling the level of color signals to modulate the density of the electron beams in a color cathode ray tube having an array of phosphors that emit light of different colors, and in which at least one of the phosphors has a luminosity saturation characteristic that is different from the others. The system includes means to limit the peak signals applied to control the beam that strikes the phosphor least subject to saturation, the purpose being to prevent that phosphor from being excited beyond the level at which the other phosphors can maintain a balanced degree of luminescence.
Abstract:
In a cathode ray tube, for example, a color picture tube in which a plurality of electron beams are made to converge or cross each other substantially at the optical center of an electrostatic focusing lens by which the beams are focused on the electron-receiving screen of the tube; the focusing lens includes first and second axially spaced, annular electrodes extending around the tube axis and being at the same potential, and a third annular electrode assembly extending between the first and second electrodes and which includes an axial array of at least three annular electrode portions, the electrode portions at the ends of the axial array being at a different potential than the first and second electrodes to establish the focusing electric field and at least one of the electrode portions intermediate the end portions being at a potential that deviates from the potential of the end electrode portions in a direction toward the potential of the first and second electrodes to modify the electric field so that its equivalent optical lens has relatively flatter surfaces for further reducing aberrations of the beam or beams focused thereby.
Abstract:
In a cathode-ray tube in which a plurality of electron beams are focused on a screen by a focusing lens from which at least certain of the beams emerge along paths divergent with respect to the tube axis, and each of the beams emerging along a divergent path is deflected to cause convergence of the beams at a common area of the screen; such deflection of each diverging beam is effected by a pair of plates at different electrical potentials disposed at opposite sides of the respective divergent path and an auxiliary electrode having open areas therein disposed along the outer side of the respective divergent path spaced inwardly from the plate which is at the side of the respective divergent path away from which the beam is deflected, this plate being at a relatively low potential and the auxiliary electrode and the other plate being at substantially the same relatively high potential to establish an electric field between the plates which, in the region thereof located between the other plate and the auxiliary electrode and being traversed by the respective beam, has a potential gradient that is maintained substantially constant irrespective of variations in the relatively high potential to avoid misconvergence due to such variations.
Abstract:
In a cathode-ray tube, for example, a color picture tube in which a plurality of electron beams are made to converge or cross each other substantially at the optical center of an electrostatic focusing lens by which the beams are focused on the electron-receiving screen of the tube; the focusing lens includes first and second axially spaced, annular electrodes extending around the tube axis and being at the same potential, a third annular electrode extending between the first and second electrodes and being at a different potential to establish the focusing electric field, and an auxiliary electrode disposed within the third electrode and connected with the first and second electrodes to modify the electric field so that its equivalent optical lens has relatively flatter surfaces for further reducing aberrations of the beam or beams focused thereby.
Abstract:
In a cathode ray tube in which a plurality of electron beams are focused on a screen by a focusing lens from which at least certain of the beams emerge along paths divergent with respect to the tube axis, and each of the beams emerging along a divergent path is deflected to cause convergence of the beams at a common area of the screen; such deflection of each diverging beam is effected by a pair of plates at different electrical potentials disposed at opposite sides of the respective divergent path to electrostatically deflect the beam therefrom, and the plate which is at the side of the respective divergent path away from which the beam is deflected is also divergent from the tube axis in the direction toward the screen so as to avoid impingement on such plate of electrons from the respective beam.